docs: def get_account(config, environment, stage=None):
      """Find environment name in config object and return AWS account."""
      if environment is None and stage:
          environment = get_environment(config, stage)
      account = None
      for env in config.get('environments', []):
          if env.get('name') == environment:
              account = env.get('account')
              role = env.get('role')
              username = os.environ.get(env.get('rs_username_var')) \
                  if env.get('rs_username_var') else None
              apikey = os.environ.get(env.get('rs_apikey_var')) \
                  if env.get('rs_apikey_var') else None
      if not account:
          sys.exit(ACCT_NOT_FOUND_ERROR.format(environment))
      return account, role, username, apikey